Intelligent drying system for preserved szechuan pickles

Abstract

The invention relates to the technical field of food processing, in particular to an intelligent drying system for preserved szechuan pickles, comprising: a drying unit used for drying preserved szechuan pickle materials in a drying chamber through a heat pump drying unit; the overturning unit is used for overturning the preserved szechuan pickle materials through a plate overturning mechanism; the reverse humidity regulation and control unit is used for spraying atomized water through a plurality of atomization nozzles so as to carry out reverse humidity regulation and control and humidity callback on the preserved szechuan pickle materials; the detection unit is used for detecting humidity data and weight data of the preserved szechuan pickle materials and environment temperature data and environment humidity data in the drying chamber in real time; the drying control unit is used for determining basic process parameters of the drying process according to the initial humidity data and the initial weight data of the preserved szechuan pickles and controlling the reverse humidity regulation and control unit to carry out reverse humidity regulation and control on the preserved szechuan pickles so as to accelerate the drying process; and controlling the reverse humidity regulation and control unit to carry out humidity callback on the preserved szechuan pickle so as to regulate the uniformity of the humidity of the inner and outer layers of the preserved szechuan pickle.

Description

Technical Field

[0001] The present invention relates to the technical field of food processing, and particularly to an intelligent drying system for pickled mustard tuber. Background Art

[0002] Air-drying and sun-drying in the production process of pickled mustard tuber are very important production links. The more traditional method is the "air dehydration method", that is, stringing fresh vegetable heads into strings with thin bamboo filaments or thin iron wires, etc., hanging them on special brackets for natural air-drying and then pickling; in modern food industry, there are various special food drying devices that can be applied to the industrial pickled mustard tuber drying process, but such drying devices usually lack the control of the drying process, can only simply set the temperature and wind force, and have low efficiency. Moreover, the drying process of pickled mustard tuber has a great impact on the subsequent pickling process of pickled mustard tuber and the tenderness and crispness of its finished products.

[0003] Chinese Patent Publication No.: CN104197653B discloses a food drying system, including: a plurality of drying box channels, a steam system, a front box door, a rear box door, a control panel and a plurality of trolleys; the drying box channels include: an exhaust system and two circulation systems, and the exhaust system is placed in the middle of the two circulation systems; the exhaust system includes: a fresh air heat exchanger, an exhaust fan, a wind valve and an exhaust duct, and the wind valve and the exhaust fan are sequentially arranged between the fresh air heat exchanger and the exhaust duct; the circulation system includes: a circulation fan, a manual wind valve and a heat exchanger, and the manual wind valve is placed between the circulation fan and the heat exchanger; the steam system includes: a steam pressure reducing valve, a steam header, a pipeline, a steam coil, a steam trap and a control valve group, the control valve group is connected to the control panel, the pipeline is connected to the heat exchanger in the circulation system, and the steam system is placed in the equipment room.

[0004] It can be seen that the food drying system has the following problems: a large amount of food materials are piled up in the drying box channels of the food drying system, resulting in uneven drying of the hot air, and moreover, it only adjusts the flow rate of the hot air according to the temperature in the drying box channels, and cannot finely control the water loss process of the food. For the vegetable materials in the food, especially pickled mustard tuber, its water loss process is divided into different stages. Using a unified temperature and wind force not only has low efficiency, but also is prone to over-water loss and skin cracking due to its long drying time, reducing the quality of pickled mustard tuber products. Summary of the Invention

[0005] Therefore, the present invention provides an intelligent drying system for pickled mustard tuber to overcome the problems of uneven drying, lack of fine control of the water loss process of food and long drying time in the prior art.

[0006] To achieve the above object, the present invention provides an intelligent drying system for pickled mustard tuber, comprising: a drying unit, which includes a drying chamber and a heat pump drying unit, for drying the pickled mustard tuber material in the drying chamber through the heat pump drying unit;

[0007] A turning unit, which is arranged inside the drying chamber, for turning the pickled mustard tuber material through a flap mechanism;

[0008] A reverse humidity control unit, which is respectively connected to the drying unit and the turning unit, for spraying atomized water through a plurality of atomizing nozzles to perform reverse humidity control and humidity callback on the pickled mustard tuber material;

[0009] A detection unit, which is arranged inside the drying chamber, for real-time detecting the humidity data and weight data of the pickled mustard tuber material, as well as the ambient temperature data and ambient humidity data inside the drying chamber;

[0010] A drying control unit, which is respectively connected to the drying unit, the turning unit, the reverse humidity control unit and the detection unit, for determining the basic process parameters of the current drying process according to the initial humidity data and initial weight data of the pickled mustard tuber, controlling the reverse humidity control unit to perform reverse humidity control on the pickled mustard tuber according to the humidity data of the pickled mustard tuber to accelerate the drying process, and controlling the reverse humidity control unit to perform humidity callback on the pickled mustard tuber according to the humidity data of the pickled mustard tuber to adjust the uniformity of the humidity of the inner and outer layers of the pickled mustard tuber.

[0011] Further, the drying control unit determines the basic process parameters of the current drying process according to the initial humidity data and initial weight data of the pickled mustard tuber, including drying temperature, wind force intensity, turning duration and turning frequency.

[0012] Further, the drying control unit determines the current drying stage according to the humidity data of the pickled mustard tuber, and determines the process parameters of the current drying stage based on the process coefficients corresponding to the current drying stage and the basic process parameters;

[0013] Among them, each drying stage at least includes a gradient drying stage for reducing the humidity of the pickled mustard tuber and an adjustment stage for adjusting the uniformity of the humidity of the inner and outer layers of the pickled mustard tuber. The gradient drying stage includes a first stage, a second stage and a third stage in which the humidity of the pickled mustard tuber decreases in sequence.

[0014] Further, in the third stage, the drying control unit controls the atomizing nozzles of the reverse humidity control unit to spray atomized water on the surface of the pickled mustard tuber material according to the humidity data of the pickled mustard tuber to perform reverse humidity control on the pickled mustard tuber;

[0015] During the adjustment stage, the drying control unit controls the atomizing nozzles of the reverse humidity regulation unit to spray atomized water vapor into the drying chamber environment according to the humidity data of the pickled mustard tuber, so as to perform a humidity callback operation on the pickled mustard tuber.

[0016] Further, the drying control unit performs a reverse humidity regulation operation in the third stage, including:

[0017] Controlling the atomizing nozzles to spray atomized water on the surface of the pickled mustard tuber material after each flipping action ends. After the spraying ends, the drying temperature is increased within a preset time and the drying temperature is adjusted back to the temperature before spraying before the next flipping action starts;

[0018] Among them, the spraying water volume, the drying temperature increase value, and the temperature increase duration are determined according to the initial weight data of the pickled mustard tuber.

[0019] Further, the drying control unit determines the reverse humidity regulation efficiency of this reverse humidity regulation according to the actual humidity change value and the humidity expected change value before and after this single reverse humidity regulation, and determines the spraying duration, the drying temperature increase value, and the temperature increase duration of the next reverse humidity regulation according to the reverse humidity regulation efficiency.

[0020] Further, the drying control unit determines the water increase amount of this reverse humidity regulation according to the change value of the ambient humidity data before and after this single reverse humidity regulation, determines the drying temperature and the wind force intensity compensation amount in the third stage according to the water increase amount and the water increase amount threshold. If the water increase amount is greater than the water increase amount threshold, the drying temperature and the wind force intensity in the third stage are increased.

[0021] Further, during the adjustment stage, the drying control unit determines the over-drying duration and the environmental water replenishment amount according to the humidity difference value between the surface and the internal flesh of the pickled mustard tuber in the oven.

[0022] Further, the drying control unit performs a humidity callback operation during the adjustment stage, including:

[0023] Controlling the drying unit to perform over-drying operation for the over-drying duration, and the over-drying duration is positively correlated with the humidity difference value; immediately after the over-drying ends, controlling the reverse humidity regulation unit to spray atomized water vapor into the drying chamber environment to increase the moisture content of the drying chamber environment, and the water replenishment amount is based on the initial value of the spraying water volume in the reverse humidity regulation and is positively correlated with the humidity difference value; after the water replenishment is completed, stop the drying unit to evenly cool the pickled mustard tuber material to obtain the dried finished product.

[0024] Further, the drying control unit compares the ambient temperature data with a preset ambient temperature threshold to determine whether it is an abnormal working condition. If the ambient temperature data is greater than the preset ambient temperature threshold, it is determined as an abnormal working condition, the reverse humidity regulation is stopped, the input of dry hot air to the drying unit is stopped, and an abnormal alarm is issued.

[0025] Compared with the prior art, the beneficial effects of the present invention are as follows. By dividing the multiple stages of the mustard tuber drying process (including the external diffusion stage, the constant rate drying stage, the deceleration drying stage, and the adjustment stage), and dynamically adjusting the drying temperature, the wind force intensity, and the flipping parameters in combination with the characteristics of each stage, the problems of skin hardening, cracking, and internal moisture residue caused by the traditional single drying mode are solved, and the quality of the mustard tuber products is significantly improved.

[0026] Further, the present invention realizes the differential drying strategy for different batches of mustard tubers by establishing the mapping relationship between the initial humidity / weight data and the basic process parameters, and avoids the phenomena of over-drying or under-drying caused by differences in loading quantity and humidity.

[0027] Further, the present invention innovatively introduces reverse humidity regulation in the deceleration drying stage. Through the synergistic effect of atomized water spraying and transient temperature increase, a "thermal shock - osmotic pressure difference" effect is formed on the surface of the mustard tuber, effectively activating the migration of deep colloidal bound water and breaking through the bottleneck of low efficiency in the deceleration stage of traditional technologies.

[0028] Further, the present invention realizes the self-correction of key parameters such as the water spraying amount and the temperature increase amplitude through the dynamic evaluation and parameter optimization of the reverse regulation efficiency. At the same time, the increased water amount is real-time feedback through the change amount of the ambient humidity, and temperature / wind force compensation is carried out after humidification, ensuring the effect of subsequent reverse humidity regulation while avoiding the increase in the time and energy consumption of secondary drying caused by excessive humidification.

[0029] Further, the present invention adds an adjustment stage, and uses the reverse humidity regulation unit to perform over-drying - water replenishing operations to balance the humidity of the mustard tuber meat and the skin, and improve the quality of the finished mustard tuber products.

[0030] Further, the present invention determines the abnormal working condition in time, stops the reverse regulation and cuts off the hot air input, effectively preventing the risks of material carbonization or mildew caused by equipment failure or environmental abnormality. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 is the connection block diagram of the intelligent drying system for mustard tubers of the present invention;

[0032] Figure 2 is the structural schematic diagram of the intelligent drying system for mustard tubers of the present invention;

[0033] Figure 3Logic flowchart of the drying control unit of the intelligent drying system for pickled mustard tuber of the present invention

[0034] Figure 4 Logic flowchart for the reverse humidity regulation of the drying control unit of the intelligent drying system for pickled mustard tuber of the present invention.

[0035] In the figure: 11 - drying chamber; 12 - tray; 13 - heat pump drying unit; 14 - distributed air inlet device; 21 - linear guide rail; 22 - driving rotating shaft; 23 - flap; 31 - atomizing nozzle; 32 - filtering device; 33 - water distribution pipe; 34 - water storage tank; 41 - infrared humidity detector; 42 - weight sensor; 43 - temperature sensor; 44 - resistive humidity sensor. Detailed implementation manners

[0036] In order to make the objectives and advantages of the present invention clearer, the present invention will be further described below in conjunction with embodiments; it should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0037] The preferred implementation manners of the present invention will be described below with reference to the accompanying drawings. Those skilled in the art should understand that these implementation manners are only used to explain the technical principles of the present invention and do not limit the protection scope of the present invention.

[0038] It should be noted that in the description of the present invention, the terms indicating directions or positional relationships such as "upper", "lower", "left", "right", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings. This is only for convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of the present invention.

[0039] In addition, it should be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installation", "connection", and "connection" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific situations.

[0040] Please refer to Figures 1 to 3 as shown, which is the connection block diagram of the intelligent drying system for pickled mustard tuber of the present invention, the structural schematic diagram of the intelligent drying system for pickled mustard tuber of the present invention, and the logic flowchart of the drying control unit of the intelligent drying system for pickled mustard tuber of the present invention.

[0041] The embodiment of the present invention provides an intelligent drying system for pickled mustard tuber, including:

[0042] A drying unit, which includes a drying chamber and a heat pump drying unit, is used to dry the pickled mustard materials in the drying chamber through the heat pump drying unit;

[0043] A turning unit, which is arranged inside the drying chamber, is used to turn the pickled mustard materials through a turning plate mechanism;

[0044] A reverse humidity control unit, which is respectively connected to the drying unit and the turning unit, is used to spray atomized water through a plurality of atomizing nozzles to conduct reverse humidity control and humidity callback on the pickled mustard materials;

[0045] A detection unit, which is arranged inside the drying chamber, is used to detect the humidity data and weight data of the pickled mustard materials in real time, as well as the environmental temperature data and environmental humidity data inside the drying chamber;

[0046] A drying control unit, which is respectively connected to the drying unit, the turning unit, the reverse humidity control unit and the detection unit, is used to determine the basic process parameters of the current drying process according to the initial humidity data and initial weight data of the pickled mustard, control the reverse humidity control unit to conduct reverse humidity control on the pickled mustard to accelerate the drying process according to the humidity data of the pickled mustard, and control the reverse humidity control unit to conduct humidity callback on the pickled mustard to adjust the uniformity of the humidity inside and outside the pickled mustard according to the humidity data of the pickled mustard.

[0047] In implementation, the drying unit includes a drying chamber 11 with a single-layer mesh tray 12 arranged inside, a heat pump drying unit 13 arranged outside the drying chamber for generating dry hot air, and a distributed air inlet device 14 arranged at the bottom of the drying chamber and communicating the drying chamber 11 and the heat pump drying unit 13 for evenly distributing and inputting the dry hot air; the turning mechanism includes linear guide rails 21 symmetrically arranged on both sides of the inner wall of the drying chamber, a driving rotating shaft 22 slidably connected to the linear guide rails, and turning plates 23 arranged on the driving rotating shaft; the reverse humidity control unit includes a plurality of atomizing nozzles 31 evenly distributed on the top inside the drying chamber for atomizing water and spraying the atomized water on the pickled mustard, a water storage tank 34 arranged outside the drying chamber, a filtering device 32 arranged outside the drying chamber for filtering water quality, and a water distribution pipe 33 arranged on the top outside the drying chamber for connecting the filtering device 32 and the plurality of atomizing nozzles; the detection unit includes a plurality of near-infrared humidity detectors 41 arranged on the top of the drying chamber for detecting the humidity data of the pickled mustard in real time, weight sensors 42 arranged at the bottom of the tray for detecting the weight data of the pickled mustard in real time, a temperature sensor 43 arranged on the side wall of the drying chamber for monitoring the environmental temperature data inside the drying chamber in real time, and a resistive humidity sensor 44 arranged on the side wall of the drying chamber for monitoring the environmental humidity data inside the drying chamber in real time.

[0048] Specifically, the drying control unit determines the basic process parameters for this drying process based on the initial humidity data and initial weight data of the pickled mustard, including the drying temperature, wind force intensity, flipping duration, and flipping frequency.

[0049] The calculation formulas for the basic process parameters: drying temperature, wind force intensity, flipping frequency, and flipping duration are all related to the initial humidity and initial weight respectively.

[0050] In a specific embodiment, for pickled mustard with a single weight of approximately 500 g, the range of the drying temperature is 40°C to 60°C, and the range of the wind force intensity is 30 m 3 / h to 40 m 3 / h; the range of the flipping frequency is 20 times / h to 30 times / h, and the range of the flipping duration is 30 s to 50 s.

[0051] In implementation, the calculation formulas for the basic process parameters are as follows:

[0052] Basic drying temperature = initial drying temperature + first humidity coefficient × (initial humidity - 60%) + first weight coefficient × initial weight, with the unit of degree Celsius (°C);

[0053] Among them, the unit of the initial drying temperature is degree Celsius (°C), preferably taking 50°C; the unit of the first humidity coefficient is degree Celsius (°C), preferably taking 40°C; the unit of the first weight coefficient is degree Celsius per kilogram (°C / kg), preferably taking 0.01°C / kg.

[0054] Basic wind force intensity = initial wind force intensity + ln(second humidity coefficient × initial humidity) + second weight coefficient × initial weight, with the unit of cubic meters per hour (m 3 / h);

[0055] Among them, the unit of the initial wind force intensity is cubic meters per hour (m 3 / h), preferably taking 25 m 3 / h; the unit of the second humidity coefficient is cubic meters per hour (m 3 / h), preferably taking 100 m 3 / h; the unit of the second weight coefficient is (m 3 / h·kg), preferably taking 0.02 m 3 / h·kg.

[0056] Basic flipping frequency = initial flipping frequency + (third humidity coefficient × initial humidity) / (1 + third weight coefficient × initial weight), with the unit of times per hour (times / h);

[0057] Among them, the unit of the initial flipping frequency is times per hour (times / h), preferably, it is taken as 15 times / h; the unit of the third humidity coefficient is times per hour (times / h), preferably, it is taken as 0.3 times / h; the unit of the third weight coefficient is (kg -1 ) and preferably, it is taken as 0.02 kg -1 .

[0058] The basic flipping duration = the initial flipping duration + the fourth humidity coefficient × the initial humidity + the fourth weight coefficient × the square root of the initial weight, and the unit is seconds (s);

[0059] Among them, the unit of the initial flipping duration is seconds (s), preferably, it is taken as 25 s; the unit of the fourth humidity coefficient is seconds (s), preferably, it is taken as 25 s; the unit of the fourth weight coefficient is seconds per kilogram (s / kg), preferably, it is taken as 0.08 s / kg.

[0060] It can be understood that the humidity data of the pickled mustard tuber is the percentage of the moisture weight of the pickled mustard tuber in the total weight, which is a dimensionless parameter; the drying temperature is the temperature of the drying hot air output by the heat pump drying unit 13. The basic drying temperature is dominated by the initial humidity and is used to reflect that the temperature needs to be preferentially increased for water evaporation; the wind force intensity is the volume of the drying hot air output by the heat pump drying unit 13 within a certain time. The basic wind force intensity decreases marginally with the increase of the value affected by the weight and humidity, and is used to ensure heat penetration while avoiding blowing away the materials; the flipping frequency is the number of flipping operations performed by the turning plate 23 within a certain time. The basic flipping frequency is an antagonistic design of humidity frequency increase and weight frequency decrease, and is used to prevent the pickled mustard tuber's epidermis and flesh from being damaged due to over-flipping; the flipping duration is the duration for the turning plate 23 to perform one flipping operation (including two flips in positive and negative directions) on all the pickled mustard tuber materials on the tray 12. High humidity and high weight both extend the contact time of flipping, and are used to ensure sufficient heat and mass transfer;

[0061] The present invention dynamically associates the basic process parameters with the initial state, avoids the finished product defects caused by still using the same process parameters when the initial water content and initial weight of each batch of materials are different, and improves the qualified rate of the finished product.

[0062] Specifically, the drying control unit determines the current drying stage according to the humidity data of the pickled mustard tuber, and determines the process parameters of the current drying stage based on the process coefficients corresponding to the current drying stage and the basic process parameters;

[0063] Among them, each drying stage at least includes a gradient drying stage for reducing the humidity of the pickled mustard tuber and an adjustment stage for adjusting the uniformity of the humidity inside and outside the pickled mustard tuber. The gradient drying stage includes a first stage, a second stage, and a third stage in which the humidity of the pickled mustard tuber decreases in sequence.

[0064] In implementation, the drying control unit determines the current drying stage according to the average value of the humidity data of the pickled mustard tuber detected in real time by each of the near-infrared humidity detectors 41.

[0065] Among them, in the gradient drying stage, when the humidity of the pickled mustard tuber is greater than 60%, it is the first stage (external diffusion stage); when the humidity drops to less than or equal to 60% and greater than 40%, it is the second stage (constant rate drying stage); when the humidity drops to less than or equal to 40% and greater than or equal to 15%, it is the third stage (decelerated drying stage); when the humidity drops to less than 15%, it is the adjustment stage.

[0066] In implementation, the actual process parameters of each gradient drying stage are the product of the basic process parameters and the process coefficients of each gradient drying stage;

[0067] Among them, the value range of the temperature coefficient is 0.8 - 1.0, which is related to the stage characteristics; the value range of the wind force coefficient is 0.7 - 1.4, which is related to the stage characteristics; the value range of the turnover frequency coefficient is 0.5 - 1.5, which is negatively correlated with the material stacking density; the value range of the turnover duration coefficient is 0.5 - 1.5, which is positively correlated with the material weight;

[0068] Preferably, the temperature coefficient of the first stage is 1.0, the temperature coefficient of the second stage is 0.8, and the temperature coefficient of the third stage is 0.9; the wind force coefficient of the first stage is 1.0, the wind force coefficient of the second stage is 0.8, and the wind force coefficient of the third stage is 1.2; the turnover frequency coefficient of the first stage is 0.5, the turnover frequency coefficient of the second stage is 1.0, and the turnover frequency coefficient of the third stage is 1.5; the turnover duration coefficient of the first stage is 1.5, the turnover duration coefficient of the second stage is 1.0, and the turnover duration coefficient of the third stage is 0.5;

[0069] Among them, the temperature coefficient and the wind force coefficient are determined through thermodynamic simulation experiments. Those skilled in the art can adjust them according to the actual situation on the premise of ensuring that each parameter can reflect the temperature demand for unit humidity change, which will not be elaborated here; the turnover frequency coefficient and the turnover duration coefficient are measured through material heat transfer experiments. Those skilled in the art can adjust them according to the actual situation on the premise of ensuring the matching of weight change with mechanical action and material adhesion degree, which will not be elaborated here.

[0070] It can be understood that the first stage corresponds to the external diffusion stage, in which a higher temperature and a greater wind force are used to quickly remove the surface free water; the second stage corresponds to the constant rate drying stage, in which a stable temperature and wind force are maintained to balance the evaporation rate; the third stage corresponds to the decelerated drying stage, in which a lower temperature and wind force than the traditional process are adopted, and reverse humidity control is used to accelerate the drying process.

[0071] Through staged coefficient adjustment, the present invention realizes the precise matching of the drying intensity and the moisture migration law, greatly improving the dehydration efficiency; at the same time, the basic parameters are dynamically associated with the initial state, avoiding insufficient drying or over-drying caused by uneven initial moisture content of each batch of materials, and improving the qualified rate of the finished product.

[0072] Specifically, please continue to refer to Figure 4 As shown, it is a logic flowchart of reverse humidity regulation of the drying control unit of the intelligent drying system for pickled mustard tuber of the present invention. The drying control unit controls the atomizing nozzle of the reverse humidity regulation unit to spray atomized water on the surface of the pickled mustard tuber material in the third stage to perform reverse humidity regulation on the pickled mustard tuber;

[0073] The drying control unit controls the atomizing nozzle of the reverse humidity regulation unit to spray atomized water vapor into the drying chamber environment according to the humidity data of the pickled mustard tuber in the adjustment stage to perform humidity callback operation on the pickled mustard tuber.

[0074] Specifically, the reverse humidity regulation operation performed by the drying control unit in the third stage includes:

[0075] Controlling the atomizing nozzle to spray atomized water on the surface of the pickled mustard tuber material after each flipping action ends, increasing the drying temperature within a preset time after the spraying ends, and adjusting the drying temperature back to the temperature before spraying before the next flipping action starts;

[0076] Among them, the spraying water volume, the drying temperature increase value, and the temperature increase duration are determined according to the initial weight data of the pickled mustard tuber.

[0077] In implementation, an anti-drip type fine atomizing nozzle is used for spraying. The particle size of the atomized water is controlled within 10μm - 30μm to ensure the efficiency of the inward penetration of the atomized water; the spraying time is controlled within 3s - 5s, and the air supply is stopped during spraying to ensure uniform coverage of the atomized water on the pickled mustard tuber; after each flip of the flip plate 23 is completed, the atomizing nozzle is started after a delay of 1s - 3s to avoid interference of material displacement on the spraying coverage; among them,

[0078] Spraying water volume = spraying water volume reference value × (initial weight / standard load capacity), unit: milliliter (mL);

[0079] Temperature increase value = temperature rise reference value × [1 + (initial weight - standard load capacity) × temperature rise coefficient], unit: degree Celsius (°C);

[0080] Temperature increase duration = temperature rise duration reference value × (initial weight / standard load capacity), unit: second (s);

[0081] Among them, the standard load capacity is obtained based on the area of the tray 12, the material density, and the power of the heat pump drying unit 13, and its value range is [150 kg, 200 kg]. Preferably, in this embodiment, it takes 150 kg; the reference value of the spraying water volume is obtained by regression analysis of the spraying effects of multiple groups of materials with different weights, and the value range is [50 mL, 120 mL]. Preferably, in this embodiment, it takes 100 mL; the reference value of the temperature rise and the temperature rise coefficient are obtained by regression analysis of the temperature rise effects of multiple groups of mustard tuber materials with different weights. Among them, the reference value of the temperature rise ranges from [5°C, 8°C]. Preferably, in this embodiment, it takes 5°C; the value range of the temperature rise coefficient is -1 , 0.008 kg -1 , and preferably, in this embodiment, it takes 0.005 kg -1 ; the reference value of the temperature rise duration is the time required for the atomized water to penetrate into the deep layer of the material measured by the dye tracer method, and the value range is [40 s, 50 s]. Preferably, in this embodiment, it takes 40 s; those skilled in the art can adjust the above parameters according to the actual situation, which will not be elaborated here.

[0082] It can be understood that the reverse humidity control is to apply controllable atomized water to the surface of the mustard tuber during the deceleration drying stage (humidity is 15% - 40%) to briefly increase the humidity of the mustard tuber epidermis and force the internal moisture to diffuse outward; then, by heating up for a short time, the micropores on the epidermis are expanded, so that the atomized water molecules carry heat into the deep layer of the mustard tuber meat; after the atomized water molecules penetrate into the deep layer of the mustard tuber, the temperature is adjusted back to generate a contraction effect, and the deep moisture including the most difficult-to-discharge colloidal bound water is "pumped" to the surface.

[0083] By actively humidifying in the later stage of the deceleration drying stage, the present invention induces "false humidity rewetting" and activates the migration of deep colloidal bound water, breaking the general consensus in the traditional technology that "continuous dehydration must be carried out during the drying process", greatly reducing the duration of the deceleration drying stage, not only reducing energy consumption, but also avoiding the skin cracking and nutrient loss caused by long-term high-temperature drying in the deceleration drying stage in the traditional technology. In practical applications, it can reduce the drying duration of the deceleration drying stage by about 20% and accelerate the drying speed.

[0084] Specifically, the drying control unit determines the reverse humidity control efficiency of this reverse humidity control according to the actual humidity change value and the humidity expected change value before and after this reverse humidity control, and determines the spraying duration, the drying temperature increase value, and the temperature increase duration of the next reverse humidity control according to the reverse humidity control efficiency.

[0085] In implementation, for a single reverse humidity control, the humidity of the pickled mustard materials is monitored once immediately after the first flipping action and before the second flipping action respectively. The difference between the second humidity monitoring result and the first detection result is the actual humidity change value before and after this reverse humidity control. Among them,

[0086] Regulation efficiency = actual humidity change value / expected humidity change value × system compensation coefficient,

[0087] If the regulation efficiency > 1.2, it indicates that the actual dehydration effect exceeds the expectation;

[0088] If 1.2 ≥ regulation efficiency ≥ 0.8, it indicates that the actual dehydration effect meets the expectation;

[0089] If the regulation efficiency < 0.8, it indicates that the actual dehydration effect is less than the expectation;

[0090] Among them, the expected humidity change value is specifically determined by the following formula:

[0091] Expected humidity change value = permeability coefficient × water spraying amount × square root of temperature increase value × ln(temperature increase duration + 10);

[0092] Among them, the permeability coefficient is measured through a dye tracer experiment to reflect the penetration efficiency of atomized water, and its value range is [0.004, 0.008], and the unit is (mL·℃·s) -1 , preferably, in the embodiment of the present invention, it takes 0.006. Those skilled in the art can adjust the permeability coefficient according to the actual situation, which will not be elaborated here.

[0093] Among them, the system compensation coefficient is determined based on the response delay characteristics of the control system and the experimental data of thermal inertia, and is used to ensure the stability of adjustment. The value range is [0.8, 1.5]. Preferably, in the embodiment of the present invention, the value is 1.0. Those skilled in the art can adjust the system compensation coefficient according to the actual situation and simultaneously adjust the determination coefficient of the regulation efficiency. For example, when the system compensation coefficient is set to 1.5, the determination coefficients of the regulation efficiency are 1.8 and 1.2; when the system compensation coefficient is set to 0.8, the determination coefficients of the regulation efficiency are 1.0 and 0.6. Other situations will not be elaborated here.

[0094] When the actual dehydration effect exceeds the expectation or the actual dehydration effect is less than the expectation, the water spraying amount, drying temperature increase value, and temperature increase duration of the next reverse humidity control are specifically as follows:

[0095] When the regulation efficiency > 1.2:

[0096] Next water spraying amount = current water spraying amount × (1 - over - efficiency attenuation coefficient);

[0097] Next drying temperature increase value = current drying temperature increase value × (1 - super - efficient attenuation coefficient × regulation efficiency);

[0098] Next temperature increase duration = current temperature increase duration × (1 - super - efficient attenuation coefficient);

[0099] When the regulation efficiency < 0.8:

[0100] Next spraying water volume = current spraying water volume × (1 + low - efficiency attenuation coefficient);

[0101] Next drying temperature increase value = current drying temperature increase value × [1 + low - efficiency attenuation coefficient × (1 - regulation efficiency)];

[0102] Next temperature increase duration = current temperature increase duration × (1 + low - efficiency attenuation coefficient);

[0103] Among them, the super - efficient attenuation coefficient and the low - efficiency attenuation coefficient are optimized through regression analysis of historical regulation data to balance the response speed and over - adjustment risk. The value range of the super - efficient attenuation coefficient is [0.05, 0.1]. Preferably, in the embodiments of the present invention, it takes 0.08; the value range of the low - efficiency attenuation coefficient is [0.1, 0.4]. Preferably, in the embodiments of the present invention, it takes 0.3; those skilled in the art can adjust the super - efficient attenuation coefficient and the low - efficiency attenuation coefficient according to the actual situation, which will not be elaborated here.

[0104] It can be understood that the determination range of the regulation efficiency is moderately relaxed to avoid misjudgment caused by heat conduction delay; when the dehydration effect is super - efficient, the parameters of reverse regulation are slightly down - adjusted to avoid energy waste caused by excessive intervention; when the dehydration effect is low - efficient, the parameters of reverse regulation are up - adjusted to prevent the mildew risk caused by the superposition of high humidity and high temperature.

[0105] The present invention realizes self - correction of key parameters such as spraying water volume and temperature increase amplitude through dynamic evaluation and parameter optimization of reverse regulation efficiency. At the same time, the regulation efficiency is determined according to physical penetration, heat conduction and time effect, and the accuracy is improved compared with the traditional empirical prediction method, which greatly improves the process stability of the reverse regulation method of the present invention.

[0106] Specifically, the drying control unit determines the water increase amount of this reverse humidity regulation according to the change value of the ambient humidity data before and after a single reverse humidity regulation, determines the compensation amount of the drying temperature and wind force intensity in the third stage according to the water increase amount and the water increase amount threshold. If the water increase amount is greater than the water increase amount threshold, the drying temperature and wind force intensity in the third stage are increased.

[0107] In implementation, for a single reverse humidity regulation, the environmental humidity of the drying chamber is monitored once immediately after the first flipping action and before the second flipping action through the resistive humidity sensor 44. The difference between the second environmental humidity monitoring result and the first detection result is the environmental humidity change value before and after this reverse humidity regulation. The water increment of a single reverse humidity regulation is calculated from the environmental humidity change before and after the regulation. Specifically:

[0108] Water increment = conversion coefficient × environmental humidity change value × drying chamber volume, with the unit of milliliter (ml);

[0109] Among them, the environmental humidity data is specific humidity, that is, the ratio between the mass of water in the air and the mass of moist air, which is a dimensionless parameter. The conversion coefficient is calibrated through a heat and humidity balance experiment, with the unit of (mL / m 3 ), and its value range is [0.05, 0.15]. Preferably, in the embodiments of the present invention, it takes 0.1. Those skilled in the art can adjust the conversion coefficient according to the actual situation, which will not be elaborated here.

[0110] The water increment threshold is specifically:

[0111] Water increment threshold = initial weight × material water absorption coefficient, with the unit of milliliter (ml);

[0112] Among them, the material water absorption coefficient is determined through an immersion experiment, with the unit of (mL / kg), and its value range is [0.1 mL / kg, 0.25 mL / kg]. Preferably, in the embodiments of the present invention, it takes 0.1 mL / kg. Those skilled in the art can adjust the material water absorption coefficient according to the actual situation, which will not be elaborated here.

[0113] If the water increment is greater than the water increment threshold, the drying temperature and wind force intensity in the third stage are increased. Specifically:

[0114] Drying temperature compensation amount = current drying temperature × temperature sensitivity coefficient;

[0115] Wind force intensity compensation amount = current wind force intensity × (water increment / water increment threshold) × wind force sensitivity coefficient;

[0116] Among them, the temperature sensitivity coefficient is determined according to a thermal inertia experiment, and its value range is [0.03, 0.07]. Preferably, in the embodiments of the present invention, it takes 0.05. Those skilled in the art can adjust the temperature sensitivity coefficient according to the actual situation, which will not be elaborated here. The wind force sensitivity coefficient is determined based on an air flow penetration efficiency experiment, and its value range is [0.05, 0.15]. Preferably, in the embodiments of the present invention, it takes 0.1. Those skilled in the art can adjust the wind force sensitivity coefficient according to the actual situation, which will not be elaborated here.

[0117] It can be understood that when the reverse humidity control of the present invention sprays atomized water on the pickled mustard tuber, some moisture will remain in the drying chamber 11, affecting the humidity environment of the drying chamber 11. The present invention reflects the humidity change of this process through the water addition amount. When the water addition amount exceeds the threshold, it will have an adverse impact on the subsequent reverse humidity control (interfering with the formation of the osmotic pressure difference and the premature restoration of the atomized water into large droplets in the air). At the same time, excessive humidification will prolong the drying time of the entire third stage. Therefore, at this time, the drying temperature and the wind force intensity are compensated.

[0118] The present invention feeds back the water addition amount in real time through the environmental humidity change amount, and performs temperature / wind force compensation after humidification, ensuring that each regulation can accurately match the current material state and environmental state, ensuring the effect of the subsequent reverse humidity control while avoiding the increase in the time and energy consumption of secondary drying caused by excessive humidification.

[0119] Specifically, in the adjustment stage, the drying control unit determines the over-drying duration and the environmental water replenishment amount according to the humidity difference value between the surface and the internal flesh of the pickled mustard tuber in the oven.

[0120] Specifically, the drying control unit performs a humidity callback operation in the adjustment stage, including:

[0121] Controlling the drying unit to perform over-drying operation for the over-drying duration, and the over-drying duration is positively correlated with the humidity difference value; after the over-drying is completed, immediately controlling the reverse humidity control unit to spray atomized water vapor into the environment of the drying chamber to increase the moisture content of the environment in the drying chamber, and the water replenishment amount is based on the initial value of the spraying water amount in the reverse humidity control and is positively correlated with the humidity difference value; after the water replenishment is completed, stop the drying unit to uniformly cool the pickled mustard tuber material to obtain the dried finished product.

[0122] In implementation, the humidity difference value between the surface and the internal flesh of the pickled mustard tuber material is detected by the near-infrared humidity detector 41. When the humidity difference value is greater than 3%, the adjustment stage is performed; the calculation formulas for the over-drying duration and the water replenishment amount are as follows:

[0123] Over-drying duration = basic over-drying duration + ln(humidity difference value × over-drying compensation duration), unit is minute (min);

[0124] Environmental water replenishment amount = spraying water amount + humidity difference value × osmotic compensation coefficient; unit is milliliter (ml);

[0125] Among them, the basic over-drying duration is determined based on the thermal inertia experiment in the decelerated drying stage, and the value range is [5 min, 10 min]. Preferably, in this embodiment, it is taken as 5 min; the over-drying compensation duration is calibrated through the gradient dehydration test, and the value range is [80 min, 160 min]: Preferably, in this embodiment, it is taken as 120 min.

[0126] It can be understood that the over-drying operation further evaporates the moisture on the surface of the pickled mustard tuber through additional drying time and temporarily makes its humidity lower than the target humidity. At the same time, it intensifies the internal and external humidity difference to form a humidity gradient from the inside to the outside (the humidity of the meat > the humidity of the skin), creating an osmotic pressure difference for subsequent water replenishment; then atomized water vapor is sprayed into the drying chamber environment to increase the moisture content of the drying chamber environment, forcing the internal water to migrate to the skin along the osmotic pressure difference to balance the internal and external humidity, and at the same time making the humidity of the pickled mustard tuber material return to the target humidity.

[0127] The present invention adds an adjustment stage, uses the reverse humidity control unit to perform over-drying and water replenishment operations, balances the humidity of the pickled mustard tuber meat and the skin, and improves the quality of the pickled mustard tuber finished product.

[0128] Specifically, the drying control unit compares the ambient temperature data with the preset ambient temperature threshold to determine whether it is an abnormal working condition. If the ambient temperature data is greater than the preset ambient temperature threshold, it is determined as an abnormal working condition, the reverse humidity control is stopped, the input of dry hot air to the drying unit is stopped, and an abnormal alarm is issued.

[0129] In implementation, the preset ambient temperature threshold is determined through the carbonization critical point experiment of the pickled mustard tuber, and the value range is [75 °C, 90 °C]. Preferably, in the embodiment of the present invention, it is taken as 80 °C.

[0130] The present invention determines the abnormal working condition, timely aborts the reverse regulation and cuts off the hot air input, effectively preventing the risk of material carbonization or mildew caused by equipment failure or environmental abnormality.

[0131] So far, the technical solution of the present invention has been described in combination with the preferred embodiments shown in the drawings. However, it is easy for those skilled in the art to understand that the protection scope of the present invention is obviously not limited to these specific embodiments. Without departing from the principle of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the protection scope of the present invention.

Claims

1. An intelligent drying system for mustard tuber, characterized in that: include: A drying unit, comprising a drying chamber and a heat pump drying unit, for drying the mustard tuber material in the drying chamber by the heat pump drying unit; A turning unit, which is arranged inside the drying chamber and is used to turn over the mustard tuber material through a turning mechanism; A reverse humidity control unit, which is connected to the drying unit and the turning unit respectively, and is used to spray atomized water through a plurality of atomizing nozzles to perform reverse humidity control and humidity adjustment on the mustard tuber material; A detection unit is arranged inside the drying chamber, and is used to detect the humidity data and weight data of the mustard tuber material, as well as the ambient temperature data and ambient humidity data inside the drying chamber in real time; A drying control unit is respectively connected to the drying unit, the turning unit, the reverse humidity control unit and the detection unit, and is used for determining basic process parameters of the drying process according to the initial humidity data and initial weight data of the pickled mustard tuber, controlling the reverse humidity control unit to perform reverse humidity control on the pickled mustard tuber according to the humidity data of the pickled mustard tuber to accelerate the drying process, and controlling the reverse humidity control unit to adjust the humidity of the pickled mustard tuber according to the humidity data of the pickled mustard tuber to adjust the uniformity of the humidity of the inner and outer layers of the pickled mustard tuber.

2. The intelligent drying system for mustard tuber according to claim 1, characterized in that: The drying control unit determines the basic process parameters of the drying process according to the initial humidity data and initial weight data of the mustard tuber, including the drying temperature, wind strength, turning time and turning frequency.

3. The intelligent drying system for mustard tuber according to claim 2, characterized in that: The drying control unit determines the current drying stage according to the humidity data of the mustard tuber, and determines the process parameters of the current drying stage based on the process coefficient corresponding to the current drying stage and the basic process parameters; Among them, each drying stage includes at least a gradient drying stage for reducing the humidity of the mustard tuber and an adjustment stage for adjusting the uniformity of the humidity of the inner and outer layers of the mustard tuber. The gradient drying stage includes the first stage, the second stage and the third stage in which the humidity of the mustard tuber is reduced in sequence.

4. The intelligent drying system for mustard tuber according to claim 3, characterized in that: In the third stage, the drying control unit controls the atomizing nozzle of the reverse humidity control unit to spray atomized water onto the surface of the mustard tuber material according to the humidity data of the mustard tuber so as to perform reverse humidity control on the mustard tuber; In the adjustment stage, the drying control unit controls the atomizing nozzle of the reverse humidity control unit to spray atomized water vapor into the drying indoor environment according to the humidity data of the pickled mustard tuber to adjust the humidity of the pickled mustard tuber.

5. The intelligent drying system for mustard tuber according to claim 4, characterized in that: The drying control unit performs a reverse humidity control operation in the third stage, including: The atomizing nozzle is controlled to spray atomized water onto the surface of the mustard tuber material after each flipping action. After the spraying is completed, the drying temperature is increased within a preset time and the drying temperature is adjusted back to the temperature before the next flipping action begins. Among them, the amount of water sprayed, the drying temperature increase value and the temperature increase time are determined according to the initial weight data of the pickled mustard tuber.

6. The intelligent drying system for mustard tuber according to claim 5, characterized in that: The drying control unit determines the reverse humidity control efficiency of the reverse humidity control according to the actual humidity change value and the expected humidity change value before and after the single reverse humidity control, and determines the spraying time, drying temperature increase value and temperature increase time of the next reverse humidity control according to the reverse humidity control efficiency.

7. The intelligent drying system for mustard tuber according to claim 6, characterized in that: The drying control unit determines the amount of water increase for the reverse humidity control according to the change in the ambient humidity data before and after the single reverse humidity control, and determines the drying temperature and wind intensity compensation amount in the third stage according to the amount of water increase and the water increase threshold. If the amount of water increase is greater than the water increase threshold, the drying temperature and wind intensity in the third stage are increased.

8. The intelligent drying system for mustard tuber according to claim 7, characterized in that: During the adjustment phase, the drying control unit determines the over-baking time and the amount of environmental water replenishment according to the difference in humidity between the skin and the internal meat of the mustard tuber in the oven.

9. The intelligent drying system for mustard tuber according to claim 8, characterized in that: The drying control unit performs a humidity callback operation in the adjustment stage, including: The drying unit is controlled to perform overdrying operation with the overdrying time, and the overdrying time is positively correlated with the humidity difference value; after the overdrying is completed, the reverse humidity control unit is immediately controlled to spray atomized water vapor into the drying room environment to increase the moisture content of the drying room environment, and the water replenishment amount is based on the initial value of the spraying water amount in the reverse humidity control and is positively correlated with the humidity difference value; after the water replenishment is completed, the drying unit is stopped to allow the pickled mustard tuber material to be evenly cooled to obtain a dried product.

10. The intelligent drying system for mustard tuber according to claim 9, characterized in that: The drying control unit compares the ambient temperature data with a preset ambient temperature threshold to determine whether it is an abnormal operating condition. If the ambient temperature data is greater than the preset ambient temperature threshold, it is judged to be an abnormal operating condition, reverse humidity control is stopped, the drying unit is stopped from inputting dry hot air, and an abnormal alarm is issued.

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